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open Import
module TextEdit = Types.TextEdit
module Position = Types.Position
module Range = Types.Range
module Simple_diff = struct
type diff =
| Deleted of { lines : int }
| Added of Substring.t Array_view.t
| Equal of { lines : int }
let line_map old_lines new_lines =
let _, map =
Array.fold_left old_lines ~init:(0, Substring.Map.empty) ~f:(fun (i, m) line ->
( i + 1
, Substring.Map.update m ~key:line ~f:(function
| None -> Some [ i ]
| Some xs -> Some (i :: xs)) ))
in
Array.map new_lines ~f:(fun x ->
Substring.Map.find_opt x map |> Option.value ~default:[])
;;
let longest_subsequence (map : int list array) old_lines new_lines =
let overlap = ref Int.Map.empty in
let sub_start_old = ref 0 in
let sub_start_new = ref 0 in
let sub_length = ref 0 in
let old_lines_pos = Array_view.backing_array_pos old_lines 0 in
let old_len = Array_view.length old_lines in
Array_view.iteri new_lines ~f:(fun inew _v ->
let overlap' = ref Int.Map.empty in
let old_indices = map.(Array_view.backing_array_pos new_lines inew) in
List.iter old_indices ~f:(fun iold ->
let iold = iold - old_lines_pos in
if iold >= 0 && iold < old_len
then (
let o = 1 + (Int.Map.find_opt (iold - 1) !overlap |> Option.value ~default:0) in
overlap' := Int.Map.add !overlap' ~key:iold ~data:o;
if o > !sub_length
then (
sub_length := o;
sub_start_old := iold - o + 1;
sub_start_new := inew - o + 1)));
overlap := !overlap');
!sub_start_new, !sub_start_old, !sub_length
;;
let get_diff old_lines new_lines =
let old_lines = Array.of_list old_lines in
let new_lines = Array.of_list new_lines in
let map = line_map old_lines new_lines in
let rec get_diff' old_lines new_lines =
match Array_view.is_empty old_lines, Array_view.is_empty new_lines with
| true, true -> []
| false, true -> [ Deleted { lines = Array_view.length old_lines } ]
| true, false -> [ Added new_lines ]
| false, false ->
let sub_start_new, sub_start_old, sub_length =
longest_subsequence map old_lines new_lines
in
if sub_length = 0
then [ Deleted { lines = Array_view.length old_lines }; Added new_lines ]
else (
let old_lines_presubseq = Array_view.sub ~pos:0 ~len:sub_start_old old_lines in
let new_lines_presubseq = Array_view.sub ~pos:0 ~len:sub_start_new new_lines in
let old_lines_postsubseq =
let start_index = sub_start_old + sub_length in
let len = Array_view.length old_lines - start_index in
Array_view.sub ~pos:start_index ~len old_lines
in
let new_lines_postsubseq =
let start_index = sub_start_new + sub_length in
let len = Array_view.length new_lines - start_index in
Array_view.sub ~pos:start_index ~len new_lines
in
List.concat
[ get_diff' old_lines_presubseq new_lines_presubseq
; [ Equal { lines = sub_length } ]
; get_diff' old_lines_postsubseq new_lines_postsubseq
])
in
let make a = Array_view.make ~pos:0 a in
get_diff' (make old_lines) (make new_lines)
;;
end
type edit =
| Insert of Substring.t Array_view.t
| Replace of
{ deleted : int
; added : Substring.t Array_view.t
}
| Delete of { lines : int }
let text_edit ~line edit =
let deleted_lines, added_lines =
match edit with
| Insert adds -> 0, Some adds
| Replace { deleted; added } -> deleted, Some added
| Delete { lines } -> lines, None
in
let start = { Position.character = 0; line } in
let end_ = { Position.character = 0; line = line + deleted_lines } in
let range = { Range.start; end_ } in
let newText =
match added_lines with
| None -> ""
| Some adds -> Substring.concat adds
in
{ TextEdit.newText; range }
;;
let split_lines =
let rec loop acc s len i =
if i >= len
then acc
else (
match String.index_from_opt s i '\n' with
| None -> Substring.of_slice s ~pos:i ~len:(len - i) :: acc
| Some j ->
let acc = Substring.of_slice s ~pos:i ~len:(j - i + 1) :: acc in
loop acc s len (j + 1))
in
fun s -> List.rev @@ loop [] s (String.length s) 0
;;
let edit ~from:orig ~to_:formatted : TextEdit.t list =
let line, prev_deleted_lines, edits_rev =
let orig_lines = split_lines orig in
let formatted_lines = split_lines formatted in
Simple_diff.get_diff orig_lines formatted_lines
|> List.fold_left
~init:(0, 0, [])
~f:(fun (line, prev_deleted_lines, edits_rev) edit ->
match (edit : Simple_diff.diff) with
| Deleted { lines = deleted_lines } ->
line, deleted_lines + prev_deleted_lines, edits_rev
| Added added_lines ->
let edit =
text_edit
~line
(if prev_deleted_lines > 0
then Replace { deleted = prev_deleted_lines; added = added_lines }
else Insert added_lines)
in
line + prev_deleted_lines, 0, edit :: edits_rev
| Equal { lines } ->
let edits_rev =
if prev_deleted_lines > 0
then text_edit ~line (Delete { lines = prev_deleted_lines }) :: edits_rev
else edits_rev
in
line + prev_deleted_lines + lines, 0, edits_rev)
in
List.rev
@@
if prev_deleted_lines > 0
then text_edit ~line (Delete { lines = prev_deleted_lines }) :: edits_rev
else edits_rev
;;